Electric device and method for charging and discharging battery unit of the same

ABSTRACT

An electric device comprises a plurality of detachable battery units ( 2, 3, 4 ), each consisting of a set of storage battery packs ( 2 B,  3 B,  4 B) and memories ( 11, 12, 13 ) storing information about the charge and discharge states of the battery packs. Connectors are provided to connect and disconnect an electric device ( 1 ) electrically incident to each battery unit being attached or detached. The device includes a driver ( 9 ) for driving a load, a charger ( 5 ) for charging the storage battery packs ( 2 B,  3 B,  4 B) by referring to the information stored in the memories ( 11, 12, 13 ) of the respective mounted battery units ( 2, 3, 4 ), and a controller ( 6 ) for controlling the electric power supplied from the individual battery units ( 2, 3, 4 ) to the driver ( 9 ) by referring to the above-mentioned information.

TECHNICAL FIELD

The invention relates to an electric device such as an electric vehicleof an electric bicycle, an electric wheelchair, or the like usingelectric energy by a battery as a power supply and a method for chargingand discharging a battery unit of the electric device.

BACKGROUND TECHNOLOGY

There is an electric vehicle such as an electric bicycle or an electricwheelchair on which a storage battery pack composed of a plurality ofstorage batteries is mounted as a power supply. The vehicles of thistype include one running only on a driving force of a motor driven byelectric energy (electric power) from the mounted storage battery pack,one running on the resultant force of a driving force of a motor andhuman power, one selectively using a driving force of a gasoline engineand a driving force of a motor, and the like.

The storage battery mounted on these vehicles as a power supply needs tobe frequently charged, and there are methods for charging it, that is, asimplex charging method of charging the battery detached from thevehicle and a mounted-on-vehicle charging method of charging the batterymounted on a vehicle.

For example, a storage battery of a large capacity with a heavy weight,as compared to the weight of a vehicle main body, may need to be mountedon an electric device such as an electric vehicle. In this case, it isdifficult to detach and carry the storage battery by hand because of theheavy weight thereof. For this reason, the vehicle, an electric device,is provided with a charging apparatus, and the vehicle is moved and neara commercial power supply. Meanwhile, in the case of a storage batterymounted on the vehicle with a relatively light weight, one charge methodis detaching the storage battery from the vehicle and connecting it to acharging apparatus, which is separately positioned.

A conventional electric device using a storage battery pack as thestorage battery and a method for charging the storage battery pack areexplained here using FIG. 15 to FIG. 20B.

FIG. 15 to FIG. 17 show examples of an electric device on which abattery section and a charging apparatus therefor are fixedly mounted.Each of electric devices 200, 210 and 220 is composed of a chargingapparatus 201, a battery section 202, a controlling apparatus 203, and adriving apparatus 204, which are connected in parallel, and a motor 205,which is driven by the driving apparatus to drive a running section suchas wheels.

In each of these electric devices, electric power from battery section202 is supplied to the driving apparatus 204 to drive the motor 205,whose motive power drives the running section, such as wheels. Thecontrolling apparatus 203 controls action of the driving apparatus 204.

The electric device 200 shown in FIG. 15, on which a set of storagebattery pack 202 a composed of, for example, a lead storage battery ismounted as the battery section 202, is often used for an electricwheelchair, an electric scooter, or the like. The weight of the batterysection 202 in the case of the storage battery pack 202 a, composed ofthe lead storage battery is as heavy as about 30 kg to 60 kg.

On the electric device 210 shown in FIG. 16, plural sets of storagebattery packs 202 a are mounted as the battery section 202, which can beconstituted by connecting in parallel m rows of storage battery packs202 a each of which is constituted by connecting n single storagebatteries in series.

The electric device 220 shown in FIG. 17 has thereon a plurality of (mpieces) storage battery pack units 202 b connected in parallel as thebattery section 202, in which each storage battery pack unit 202 b isconstituted by connecting n single storage batteries in series.

These electric devices 210 and 220 are heavily used for an electricvehicle operated for a long time, an electric device for moving anobject having a large weight, an electric fork lift or an electriccarrier vehicle requiring a large capacity or a power supply of bulkpower. These devices often have a battery section 202 having a weight ofmore than about 60 kg.

Since each of the electric devices 200, 210 and 220 has thereon thebattery section 202 and the charging apparatus 201 for charging it,charging is performed for the storage battery pack or packs 202 a or thestorage battery pack units 202 b of the battery section 202 by moving ortransporting the electric device together with the vehicle near acommercial power supply 100, connecting the commercial power supply 100to the charging apparatus 201, and supplying a charging current to thebattery section 202 by the charging apparatus 201. Alternatively, thebattery section 202 can be detached from the vehicle and charged by aspecial apparatus.

It should be noted that in the electric devices 210 and 220 shown inFIG. 16 and FIG. 17, it is also possible to charge and discharge aplurality of storage battery packs 202 a or storage battery pack units202 b as a unit, each constituting the battery section 202.

On the other hand, electric devices 300,310 and 320 shown in FIGS. 18A,19A and 20A have no charging apparatuses thereon, and chargingapparatuses 301 respectively shown in FIGS. 18B, 19B and 20B areprovided in a garage or at a rest area. Each battery section 302 in FIG.18, FIG. 19A or FIG. 20A is composed of storage battery packs 302 a orstorage battery pack units 302 b, as in the battery section 202 in FIG.15, FIG. 16 or FIG. 17, but is a unit attachable/detachable to/from themain body of the electric device 300, 310 or 320 and provided withconnectors 306 a and 306 b for establishing electrical connection to themain body. The other structures are the same as in the electric devicesshown in FIG. 15 to FIG. 17.

When charging is performed for the battery section 302 detachablymounted on the electric device 300, 310 or 320, the charging isperformed by detaching the battery section 302 from the device main bodyand moving and installing it in the charging apparatus 301, which isseparately placed and connected to the commercial power supply 100, asshown in FIG. 18B, FIG. 19B or FIG. 20B.

As the storage battery packs 302 a or the storage battery pack units 302b of the battery section 302, for example, a nickel-cadmium (Ni—Cd)battery having a relatively light weight of about 1.8 kg to 3.5 kg isused and mounted on an electrically assisted bicycle or the like.

When a not-so-large battery capacity and supply power of the batterysection are required, as in the electrically assisted bicycle, thebattery section is of a weight easily portable by human power, and thusit is easy to detach the battery section from the vehicle for charging.

However, the battery section of a typical electric device isinconvenient because it has a considerably heavy weight. Charging shouldbe performed by moving the electric device (vehicle) itself to a placehaving a chargeable power supply, such as the commercial power supply orthe like, or by transporting the battery section using a transporter toa place where a charging apparatus is provided.

Further, since only one of (one set of) battery section 202 or 302 ismounted on the above-described electric device, when the battery sectionbecomes unusable because the storage state of its storage battery packsfall below a predetermined specified value (which is decided inaccordance with specifications of the battery, requirements for theelectric device, and the like), the electric device itself becomesunusable, even if the controlling apparatus, the driving apparatus, andthe like, except the battery section, are usable. Thus, if the batterysection is detachable, the battery section which becomes unusable shouldbe exchanged for another battery section for powering the electricdevice.

Alternatively, it is necessary to charge the battery section, which hasbecome unusable because the storage state of its storage battery packfalling below the specified value. In this case, there is an additionalproblem that it takes a long time to charge the battery section enoughto make the electric device usable, unless a charging apparatus having acapacity large enough is used.

Furthermore, as for the battery section, when the battery section isconstituted by connecting in parallel a plurality of storage batterypacks or storage battery pack units as in the above-described electricdevice shown in FIG. 16 and FIG. 17 or FIG. 19A and FIG. 20A, it isnecessary to limit the variation in the charge amount to within anallowable range or to provide means for controlling it so as not tocause the variation among the storage battery packs or the storagebattery pack units.

Especially when a nickel-cadmium (Ni—Cd) battery, a nickel metal hydride(Ni-MH) battery, or the like is used for the battery section, aso-called memory effect occurs such that the capacity of the batterydecreases due to the use of the battery while charging and dischargingare repeated with the discharge depth being shallow, and thus means forpreventing this is necessary.

Further, when regenerative electric power from a load side, such as amotor or the like, is recovered for the battery section, charging oftenbecomes impossible, depending on the state of the battery section or thedegree of discharge, which prevents the regenerative electric power frombeing stored efficiently.

Therefore, a method of supplying power for an electric vehicle and anapparatus therefor are proposed which are configured such that storagebattery packs each having a required capacity are mounted in a dividedform in accordance with characteristics of an electric vehicle, and thestorage battery packs are made connectable in series or in parallel tobe charged or discharged singly or in combination as required, therebyimproving the radiation property of the heat from the storage batterypacks during charge and discharge to reduce the deterioration caused byheat so as to prolong storage battery pack life, and further theremaining capacities and the charge states of the storage battery packscan be recognized easily (See JP, 9-298805, A)

In this electric vehicle, the storage battery packs are connected inparallel to produce a large current when its load is large at the timeof starting, accelerating, or the like, and a single or a plurality ofthe storage battery packs as required discharge a small current when itsload becomes smaller at the time of traveling at a constant speed afterthe start, or the like.

The plurality of the storage battery packs are mounted and fixed on thevehicle in a manner not to contact each other.

Further, the management of the storage battery packs in this electricvehicle is conducted based on the use of the storage battery packs in afully charged state and by a method of discharging one of the pluralityof the storage battery packs and, after the charge the storage batterypack depletes, discharging the next storage battery pack.

As described above, this electric vehicle is configured such that theplurality of the storage battery packs discharge on a one-set basis andthe remaining capacities of the remaining storage battery packs can bedisplayed when the above discharge ends, to enable easy recognition ofthe remaining capacities of the storage battery packs in the wholedevice. In the case of charging the storage battery packs, control ofthe device is conducted so that the charge is performed in a reverseorder to that of the discharge. In other words, charge needs to beperformed to be a full charge without fail.

However, since the plurality of the storage battery packs connected inparallel discharge respectively when a large current discharge isrequired because of a large load at the time of starting, accelerating,or the like, and a single or a plurality of the storage battery packs asrequired discharge a small current at the time of a light load such asat traveling at a constant speed, it is difficult to appropriatelymanage the remaining capacities of the storage battery packs, whichpresents the problem that it is impossible to conduct control for themost efficient charge and discharge.

Especially when using the storage battery packs in which a so-calledmemory effect occurs that the capacity of the battery decreases due tothe use of it while charge and discharge are repeated with the dischargedepth being shallow, it is desirable to conduct an optimal charge anddischarge control for individual storage battery packs to prevent thememory effect, but such control is difficult.

Further, when the storage battery packs, which have ended discharge tothe specified remaining capacities, are detached from the vehicle andcharged by a charging apparatus at another place, it is impossible tocheck the charge and discharge states thereof with the storage batterypacks detached and then conduct an optimal control because of thebatteries being under standardized sequential management.

It is an object of the invention to solve the above-described problemsin the conventional electric device and to enable an appropriatemanagement and an efficient use, all the time, of a battery sectionprovided with storage battery packs. More specifically, matters listedin the following are its objects.

(1) To facilitate detachment and carrying of the battery section by handto eliminate the need to move the electric device at the time ofcharging and to eliminate the need for a special carrier fortransporting the battery section.

(2) To improve usage of the battery section in the electric device forease of use.

(3) To make it possible to perform operation and charge of the electricdevice in parallel without need for a special charging apparatus.

(4) To make it possible to manage battery characteristics of the batterysection and freely select charge and discharge in accordance with thebattery characteristics.

(5). To prevent a so-called memory effect when a secondary battery(storage battery), such as a Ni—Cd battery, in which the memory effectoccurs is used as the battery section of the electric device and toeliminate the need for refresh thereof.

(6) To improve detection accuracy of charge and discharge states of theindividual storage battery packs in the plurality of the batterysections.

(7) To prolong storage battery pack life.

(8) To make it possible to use even different types of storage batterypacks in combination.

(9) To facilitate charge by placing the charging apparatus at a batterystation and to make it possible to recognize the charge and dischargestates of the battery section at a high accuracy, even when it isdetached from the electric device so as to enable an optimal chargecontrol.

Further, to recover the regenerative electric power from a load sidesuch as a motor or the like to the battery section so as to utilize itefficiently.

DISCLOSURE OF THE INVENTION

To achieve the above-described objects, the invention provides anelectric device and a charging apparatus for charging a battery unitthereof, and a method for charging and discharging the battery unit asfollows.

The electric device according to the invention comprises: a plurality ofbattery units detachably mounted thereon, each battery unit constitutedby pairing a storage battery pack with a memory for storing at leastinformation about charge and discharge states of the storage batterypack; and connectors provided on each battery unit and a battery unitinstallation section on a device main body side, for performingelectrical connection/disconnection to/from the device main body sideincident to attachment/detachment of the battery unit.

Additionally, a driver for driving a load, a charger for charging thestorage battery pack by referring to the information stored in thememory of each mounted battery unit, and a controller for controllingthe supply of electric power from each battery unit to the driver byreferring to the information stored in the memory of each mountedbattery unit, which are provided on the device main body side, and thecharger includes means for reading at least the information about chargeand discharge states of the storage battery pack stored in the memory ofeach battery unit, and means for writing into the memory at least theinformation about charge and discharge states of the storage batterypack in the same unit.

Here, the storage battery pack includes various types of secondarybatteries such as a nickel-cadmium battery and a nickel metal hydridebattery. The memory is a nonvolatile memory such as an EEPROM, a flushROM, a RAM backed up by a battery, or the like, into which various kindsof information are written which include at least the information aboutcharge and discharge states of the storage battery pack by the chargeror the controller provided in the battery unit or on the electric devicemain body side. In addition, the information of the type andcharacteristics of the storage battery pack can also be written intothem in advance.

As for this battery unit, the charge and discharge states of the storagebattery pack included therein can be recognized precisely by referringto the information stored in its memory, even when it is mounted on theelectric device or it is detached therefrom to be in a single state, andthus an appropriate charge and discharge control can be conducted allthe time.

The electric device may comprise: a plurality of battery unitsdetachably mounted thereon, each battery unit constituted by integratinga storage battery pack, a memory for storing at least information aboutcharge and discharge states of the storage battery pack, and a chargerfor charging the storage battery pack; connectors provided on eachbattery unit and a battery unit installation section on a device mainbody side, for performing electrical connection/disconnection to/fromthe device main body side incident to attachment/detachment of thebattery unit; and a driver for driving a load and a controller forcontrolling supply of electric power from each battery unit to thedriver by referring to the information stored in the memory of eachmounted battery unit, which are provided on the device main body side.

In this case, the charger of each battery unit has means for deciding acharge order by mutually referring to the information stored in thememory of each mounted battery unit.

Further the electric device may comprise: a plurality of battery unitsdetachably mounted thereon, each battery unit constituted by pairing astorage battery pack with a memory for storing at least informationabout charge and discharge states of the storage battery pack, andprovided with a switch connected to the storage battery pack in series;connectors provided on each battery unit and a battery unit installationsection on a device main body side, for performing electricalconnection/disconnection to/from the device main body side incident toattachment/detachment of the battery unit; and a driver for driving aload, a charger for charging the storage battery pack through the switchby referring to the information stored in the memory of each mountedbattery unit, and a controller for controlling supply of electric powerfrom the storage battery pack to the driver through the switch of thebattery unit by referring to the information stored in the memory ofeach mounted battery unit, which are provided on the device main bodyside, and the charger may include means for reading at least theinformation about charge and discharge states of the storage batterypack stored in the memory of each battery unit, and means for writinginto the memory at least the information about charge and dischargestates of the storage battery pack in the same unit.

With these electric devices, a plurality of battery units can bedetachably mounted thereon, and one or more battery units suitable fordischarge can be selected based on the information about charge anddischarge states of the storage battery packs stored in the memoriesprovided in the battery units to allow them to discharge so as to supplyelectric power to the driving section.

Also in the case of charging the storage battery packs of the batteryunits, the charge can be selectively performed, while an optimal controlis being conducted, for a single or a plurality of battery units by thecharging apparatus provided on the device main body side, the chargingapparatus provided in each battery unit, or the charging apparatusprovided at a charger station based on the information about charge anddischarge states of the storage battery packs stored in the storageapparatus in the battery units.

In these electric devices, the charger which is provided separately fromthe aforementioned battery unit can also be structured to be a unitattachable/detachable to/from the electric device main body, so that thecharger (charger unit) can be detached, together with one or morebattery units, from the electric device to charge the storage batterypacks of the battery units.

Furthermore, it is desirable that the controller has means for readingthe information about charge and discharge states of the storage batterypack stored in the memory of each battery unit and holding it therein,and means for controlling action of the whole device based on theinformation stored in the former means.

Moreover, it is possible that the memory of each battery unit alsostores information about characteristics of the storage battery pack,and the charger has means for controlling charge of the storage batterypack, by referring to the information about the characteristics of thestorage battery pack stored in the memory of each battery unit, inaccordance with the characteristics.

Further, it is suitable that the controller has means for controllingdischarge from the storage battery pack, by referring to the informationabout the characteristics of the storage battery pack stored in thememory of each battery unit, in accordance with the characteristics.

Further, in these electric devices, the controller desirably has meansfor displaying a remaining capacity of the storage battery pack of eachbattery unit based on the information stored each battery unit, anddisplaying a charge request and/or giving an alarm when a storagebattery pack needing to be charged exists.

A method for charging and discharging the battery unit in the electricdevice according to the invention comprises the steps of discharging inorder the storage battery packs of the battery units mounted on theelectric device to a predetermined remaining capacity and then chargingthem, by referring to the information stored in the memoriesrespectively.

Alternatively, it is preferable to discharge the storage battery packsof the battery units mounted on the electric device in decreasing orderof remaining capacity, and to charge them in increasing order ofremaining capacity, by referring to the information stored in thememories respectively.

Further, it is also preferable to discharge the storage battery packs ofthe battery units mounted on the electric device in increasing order ofremaining capacity, and to charge them when the remaining capacitiesbecome a predetermined value or less, by referring to the informationstored in the memories respectively.

Furthermore, it is also preferable to select one or more of batteryunits mounted on the electic device an discharge storage battery packsthereof, and to select remaining one or more battery units and chargestorage battery packs thereof, by referring to the information stored inthe memories respectively.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block circuit diagram of an electric device showing a firstembodiment of the invention on which battery units are mounted;

FIG. 2 is a block circuit diagram of an electric device showing a secondembodiment of the invention on which battery units are mounted;

FIG. 3 is a block circuit diagram of an electric device showing a thirdembodiment of the invention on which battery units are mounted;

FIG. 4 is a diagram showing a connecting state where charge is performedwith a charger unit and a plurality of the battery units detached fromthe electric device shown in FIG. 1;

FIG. 5 is a diagram where charge is performed with one battery unitdetached from the electric device shown in FIG. 2;

FIG. 6 is a diagram showing a connecting state where charge is performedwith a charger unit and a plurality of the battery units detached fromthe electric device shown in FIG. 3;

FIG. 7 is a flowchart showing a charge action for the battery units by acharger in the electric device shown in FIG. 1;

FIG. 8 is a subsequent flowchart of the same;

FIG. 9 is a flowchart showing an action by a controlling apparatusduring operation of the electric device shown in FIG. 1;

FIG. 10 is a subsequent flowchart of the same;

FIG. 11 is a flowchart showing an individual charge action by thecharger of each battery unit in the electric device shown in FIG. 2;

FIG. 12 is a flowchart showing an action where the chargers in thebattery units in the electric device shown in FIG. 2 send/receiveinformation each other to sequentially charge storage battery packs;

FIG. 13 is a flowchart showing an action where the chargers in thebattery units in the electric device shown in FIG. 2 send/receiveinformation to each other to charge the storage battery packs whilecontrolling charging power;

FIG. 14 is a subsequent flowchart of the same;

FIG. 15 is a block diagram showing an example of a conventional electricdevice on which a storage battery pack and a charging apparatus thereforare mounted;

FIG. 16 is a block diagram showing another example of a conventionalelectric device on which storage battery packs and a charging apparatustherefor are mounted;

FIG. 17 is a block diagram showing still another example of aconventional electric device on which storage battery packs and acharging apparatus therefor are mounted;

FIGS. 18A and 18B are block diagrams showing an example of a chargestate of the storage battery pack by a charging apparatus which isprovided separately from the conventional electric device on which thestorage battery pack is mounted;

FIGS. 19A and 19B are block diagrams showing another example of a chargestate of the storage battery packs by a charging apparatus which isprovided separately from the conventional electric device on which thestorage battery packs are mounted;

FIGS. 20A and 20B are block diagrams showing still another example of acharge state of the storage battery packs by a charging apparatus whichis provided separately from the conventional electric device on whichthe storage battery packs are mounted; and

FIG. 21 is a diagram showing a controller with a display and an alarm.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the invention will be describedwith reference to the drawings.

An electric device having a battery unit mounted thereon, an apparatusfor charging the battery unit, and a method for charging and dischargingthe battery unit in the electric device according to the invention areexplained in roughly divided three embodiments in order, in each ofwhich the electric device including the above categories is mainlyexplained.

It should be noted that basically the electric device according to theinvention is detachably equipped with a battery unit, in which a storagebattery pack is always paired for integration with a memory for storingat least information about charge and discharge states of the storagebattery pack (preferably including information about characteristic ofthe storage battery pack).

First Embodiment

FIG. 1 is a block circuit diagram of an electric device showing thefirst embodiment of the invention on which battery units are mounted.

An electric device 1 of this embodiment has a plurality of battery units2, 3 and 4, and a common charger unit 8 for charging respective storagebattery packs 2B, 3B and 4B thereof, which are detachably mounted on thedevice main body (not shown) respectively.

The battery units 2, 3 and 4, having the same structure, are units inwhich the storage battery packs 2B, 3B and 4B are paired for integrationwith memories 11, 12 and 13 such as EEPROMs or the like. The batteryunits 2, 3 and 4 and battery unit installation sections (not shown) onthe device main body are provided respectively with connectors Ba1, Ba2and Ba3, connectors Bb1, Bb2 and Bb3, and connectors Bc1, Bc2 and Bc3,each of which is composed of paired terminals, as connecting means forelectrically connecting and disconnecting the battery units 2, 3 and 4to/from the device main body incident to attachment and detachment ofthe battery units 2, 3 and 4.

The charger unit 8 is a unit containing therein a charger 5 having amicrocomputer and switches SW21, SW22 and SW23 corresponding to each ofthe battery units 2, 3 and 4, and is provided with connectors Cp1, Cp2,Cp3, Cg1, Cg2, Cg3, Cs1, Cs2 and Cs3, each of which is composed ofpaired terminals, between the charger unit 8 and the charger unitinstallation sections (not shown) of the device main body, as connectingmeans for electrically connecting and disconnecting the charger unit 8to/from the device main body side incident to attachment and detachmentof the charger unit 8.

Further, the electric device 1 comprises, on the main body side, acontroller 6 for controlling the action of the whole electric device 1,a controlling power supply 7 and a driver 9 connected thereto, a load 10of the electric motor and the like which is driven by the driver 9 todrive a running section (not shown), and three switches SW11, SW12 andSW13 interposed in discharge (feed) lines from the battery units 2, 3and 4 to the controller 6 and the driver 9.

The charger 5 in the charger unit 8 has a function of charge controllingthe storage battery packs 2B, 3B and 4B of the battery units 2, 3 and 4,and a function of reading and writing information from/into the memories11, 12 and 13. Further, the controller 6 similarly has therein afunction of reading and writing information from/into the memories 11,12 and 13 of the battery units 2, 3 and 4 in addition to a function ofcontrolling all signals.

The charger 5 receives supply of alternating-current power from acommercial power supply 100, rectifies and smoothes it to make it directcurrent, and converts it to an output voltage suitable for charge.Further, the charger 5 reads and temporarily stores the informationabout the charge and discharge states of the storage battery packs 2B,3B and 4B from the memories 11, 12 and 13 of the plurality of themounted battery units 2, 3 and 4, and selectively turns on one of theswitches SW21, SW22 and SW23 by a switch 2 n control signal to chargethe storage battery pack of the battery unit selected based on theinformation.

FIG. 1 shows an example in which three battery units are mounted, butthe object of the invention can be achieved by mounting two or morebattery units. In addition, the charger unit 8 is also detachablymounted on the main body of the electric device 1, so that it can easilybe detached from the electric device 1 and used outside the electricdevice 1, but it may be provided fixedly to the main body of theelectric device 1.

Each of the storage battery packs 2B, 3B and 4B of the battery units 2,3 and 4 is constituted by connecting in series a plurality of chargeablestorage batteries or secondary batteries.

In each of the memories 11, 12 and 13 of the battery units 2, 3 and 4,information specific to a battery such as a rated capacity, temperaturecharacteristics, preservation characteristics and the like, andinformation about the charge and discharge states of the battery, suchas an amount of charge, an amount of discharge, numbers of charges anddischarges and the like of each of the storage battery packs 2B, 3B and4B, are stored.

As described above, the battery units 2, 3 and 4 have individualinformation respectively, which allows the plurality of the batteryunits 2, 3 and 4 to be attached and detached in any order. The switchesSW11, SW12 and SW13 which are provided in respective feed lines betweenthe battery units 2, 3 and 4, and, the controller 6 and the driver 9,are selectively turned ON by an SW1 n control signal controlled based onthe controlling function of the controller 6, and used for selectingwhich battery unit is used to feed power to the controller 6 and thedriver 9.

The controller 6, having a microcomputer therein, detects installationstates of the plurality of the battery units 2, 3 and 4 by thecontrolling function in conjunction with the reading/writing function,reads and temporarily stores the information stored in the memories 11,12 and 13 in the battery units 2, 3 and 4, selects a battery unit to bedischarged based on the information, and controls its dischargingcurrent, discharging voltage and the like, to thereby conduct managementappropriate for the battery characteristics of the battery unit used andthe characteristics of the electric device 1 when necessary.

Further, it is also possible to display, for example, on a display 35(FIG. 21), information of each of the mounted battery units, forexample, the remaining battery capacity of the individual or the totalof the plurality of the mounted battery units, charge request when thereis a battery unit needing to be charged and the like, or to give analarm and the like, for example, using an alarm 36 (FIG. 21), whennecessary. In other words, this controller 6 has functions ofcontrolling ON/OFF states of the switches SW11, SW12 and SW13 andmanaging and controlling the whole electric device 1, based on theinformation stored in the memories 11, 12 and 13 of the battery units 2,3 and 4.

The controlling power supply 7 has a function of supplying requiredpower to the controller 6 when at least one of the battery units 2, 3and 4 is mounted on the electric device 1. The controlling power supply7 is supplied with electric power also when at least one storage batterypack among the battery units is charged by the charger 5, and in thisevent the controlling power supply 7 operates when necessary to supplyelectric power to the controller 6.

Further, when each of the battery units 2, 3 and 4 is detached or when acommand to stop the electric device 1 is given or the like, thecontrolling power supply 7 supplies electric power to the controller 6until the controller 6 stops drive of the load 10 by the driver 9,writes information about charge and discharge states and the like of thestorage battery packs of an operating battery unit among the batteryunits 2, 3 and 4 into the memory in the battery unit, stops the electricdevice 1 in safety, and the like, to thereby complete necessaryprocessing.

The driver 9 receives supply of electric power from single orcombination, as required, of the plurality of the battery units 2, 3 and4 mounted on the electric device 1, to drive and control the load 10such as an electric motor, an actuator, a group of lamps and the like.

The electric motor of the load 10 drives a not shown running sectionsuch as wheels to thereby cause the electric device 1 to run. Theactuator operates a brake and the like. The group of lamps includeslamps such as a headlight, a taillight, blinkers (winkers).

Moreover, when it is necessary to detect a charging current and adischarging current in accordance with purposes, accurate informationabout the charging current and/or the discharging current can beobtained by providing, for example, current detectors, not shown, atpoints in connection lines from the connectors Ba2, Bb2 and Bc2 to thebattery units 2, 3 and 4 where charge and discharge can be detected.

In the same manner, an accurate voltage or temperature information ofeach of the storage battery packs 2B, 3B and 4B in the battery units 2,3 and 4 can be obtained by providing a voltage detector for detectingthe voltage of a plurality of individual battery cells or the whole cellblock, or a temperature detector for detecting temperature of theindividual battery cell or the whole cell block, in accordance withcharacteristics of the storage battery pack used in each of the batteryunits 2, 3 and 4. Since these detectors are also configured to bedetachably attached to the device main body together with the respectivebattery units 2, 3 and 4, they need connectors for their signal lines.

Next, charge action for the battery units 2, 3 and 4 in the electricdevice 1 shown in FIG. 1 is explained.

When the charger 5 in the charger unit 8 is supplied with the commercialpower supply 100 or an alternative power supply to go into the chargeaction, the microcomputer in the charger 5 first accesses each of thememories 11, 12 and 13 in the plurality of the battery units 2, 3 and 4to detect the existence or absence of the installation thereof, andreads and obtains the information stored in the memories of theinstalled battery units, and holds the obtained information in thememory included in the charger 5 if necessary. This allows the charger 5to recognize the information about the charge and discharge states andthe like of the storage battery packs 2B, 3B and 4B in the battery units2, 3 and 4 installed in the electric device 1. The charger 5 selects,for example, a battery unit for which charge will be completed theearliest based on the recognized information of each of the batteryunits 2, 3 and 4, and turns on any one of the switches SW21 to SW23 bythe SW2 n control signal, to go into charge action for the storagebattery pack of the selected battery unit.

After the completion of the charge of the battery unit, the charger 5writes charge information such as increase in the number of charges,full charge information, the integrated charge amount, temperature incharging, and the like into the memory of the battery unit for which thecharge has been completed, and then starts charging a battery unitneeding to be charged next. The charger 5 conducts the charge untilbattery units needing to be charged no longer exist among the pluralityof the mounted battery units, and when the charge is completed, thecharger 5 ends the charge action.

Further, even when the charge action is suspended at some midpoint ofthe charge because of some reasons, the charge information until themidpoint is stored in the memory provided in the battery unit incharging as in the case of the completion of the charge, so that theabove information can be utilized at the time of charging anddischarging the battery unit. The above-described charge action isexplained using flowcharts in FIG. 7 and FIG. 8.

When the charger 5 in the charger unit 8 in FIG. 1 goes into the chargeaction shown in the flowcharts in FIG. 7 and FIG. 8, it first accesses astorage in a battery unit installed in a first position (the memory 11in the battery unit 2 in this example) as shown in FIG. 7 to read theinformation (data) stored therein.

Then, the charger 5 determines whether the data is normal or not. Thecircuit is configured to erase data to zero when no battery unit isinstalled. In this case, it is appropriate, for example, to providechecksum data and to use means for checking it.

If the result of the determination whether the data is normal or not isnormal (Y), the charger sets a flag indicating that the battery unit isinstalled in the first position, and if the result is abnormal (N), thecharger 5 performs nothing, and then it accesses a storage in a secondposition (the memory 12 in the battery unit 3 in this example) to readthe information (data) stored therein.

Subsequently, the charger 5 determines whether the data is normal ornot, and if it is normal (Y), the charger 5 sets a flag indicating thatthe battery unit is installed in the second position, and if it isabnormal (N), the charger 5 performs nothing, and then it accesses astorage in a third position (the memory 13 in the battery unit 4 in thisexample) to read the information (data) stored therein.

Subsequently, the charger 5 determines whether the data is normal ornot, and if it is normal (Y), the charger 5 sets a flag indicating thatthe battery unit is installed in the third position, and then itproceeds to process of charge shown in FIG. 8.

When the result of the determination whether the data is normal or notis abnormal (N), the charger 5 checks whether the installation flag isset or not, and if it is set, the setting of the installation flagindicates that the battery units are installed in the first and/orsecond positions, and thus the charger 5 proceeds to the process ofcharge shown in FIG. 8. If it is not set, the charger 5 determines thatno battery units are installed in the installation positions, and endsthe charge action here.

According to the start of the charge action shown in FIG. 8, when thereare a plurality of installation flags for the battery units, the charger5 selects, for example, the battery unit for which charge will becompleted the earliest based on the information obtained from eachmemory. (information about charge and discharge states of the storagebattery pack), controls the switches SW21, SW22 and SW23 in the chargerunit 8 shown in FIG. 1 by the SW2 n control signal to connect to thebattery unit. Thereby, the charger 5 starts charging the storage batterypack of the selected battery unit.

After the start of the charge, in a typical charging method, the chargeis continued to be performed to full charge where the charge iscompleted unless a charge stop command (command based on turning off ofthe commercial power supply, charge stop operation from an operatingpanel (not shown), or the like) to suspend the charge at some midpointis given. When a charge stop command is given at some midpoint, however,the charger 5 writes the charge information about charging until theninto the memory in the battery unit which has been selected and charged,and ends the charge action.

On the other hand, after the charger 5 starts charging the storagebattery pack of the selected battery unit, it measures and computes thecharge information such as the integrated charge amount, the temperaturein charging, and the like which are previously decided as necessary inaccordance with the battery characteristics of the selected batteryunit, during the charge, by the charge controlling function thereof by apredetermined method, and holds it by the memory in the charger unit 8.

After the completion of the charge of the selected battery unit, thecharger 5 writes the charge information into the memory of the selectedbattery unit. Subsequently, the charger 5 clears the installation flagfor the battery unit.

Thereafter, the charger 5 determines whether another installation flagis set or not, and if it is not set (if it is cleared), the charger 5ends the charge action. However, when the installation flag is still set(when it is not cleared), the charger 5 returns to the first step inFIG. 8 and repeats the above described processing, that is, it selects abattery unit for which charge will be completed the earliest among theremaining battery units (a battery unit subjected to charge second) andstarts charging it. Subsequent processing is the same as performed forthe battery unit which has been charged first.

After the completion of the charge of the battery unit, when theinstallation flag for still another battery unit is set, the charger 5repeats the same action to thereby complete charge of all of the storagebattery packs of the battery units.

Naturally, when charge is not necessary for the storage battery pack inaccordance with the information from the memory of each battery unit,the charger 5 does not go into the charge action but clears only theinstallation flag to thereby end the processing for the battery unit tobe processed. This prevents an excessive charge due to recharge into thestorage battery pack of the battery unit just after charge or in a fullycharged state, which does not need to be charged.

The information here to be stored in the memories 11, 12 and 13 providedin the respective battery units 2, 3 and 4 includes information aboutthe charge and discharge states required in accordance withcharacteristics of the batteries in use (the storage battery packs 2B,3B and 4B) and characteristics of the electric device 1, for example,the number of charges, full charge information, an integrated chargeamount, temperature in charging, the number of discharges, an integrateddischarge amount, a remaining capacity, temperature in discharging, andthe like. The details of the information will be described below.

Next, the action of the electric device 1 (driving of the load 10) shownin FIG. 1 during operation is explained.

When the battery unit is installed in at least one of three battery unitinstallation sections in the electric device 1, required power issupplied to the controller 6 by the controlling power supply 7.

When the controller 6 is supplied with the power supply, it accesses thememories 11, 12 and 13 provided in the battery units 2, 3 and 4 by thecontrolling function included in the controller 6, so that thecontroller 6 obtains information of the existence or absence of theinstallation of the battery units and the information in the memoriesnecessary for discharge from the installed battery units, and holds themwhen necessary by the information storing function included in thecontroller 6.

Through this action, the battery units installed in the electric device1 are recognized as in the case by the aforementioned charger 5. Thoughillustration is omitted, when a signal requesting operation of theelectric device 1 is inputted into the controller 6, it selects, forexample, a battery unit having the least remaining capacity, based onthe above-described information necessary for the discharge, which thecontroller 6 has obtained and holds. Actually, a battery unit to bedischarged is selected in accordance with the characteristics of thestorage battery pack, the characteristics of the electric device, andthe like, and in this embodiment, an example is explained in which thebattery unit having the least remaining capacity is selected.

The controller 6 switches the switches SW11, SW12 and SW13 by the SW1 ncontrol signal and sends a signal to the driver 9 in response to theaforementioned request to cause the driver 9 to drive, for example, anelectric motor (not shown) which is the load 10 to thereby operate theelectric device.

When the battery unit, which has been selected and being discharged,comes into a predetermined end-of-discharge state, the controller 6writes the discharge information into the memory of the battery unit.Then, the controller 6 selects a battery unit to be discharged nextbased on the information from the memories of other installed batteryunits or the information which has been obtained and stored, andswitches between the switches SW11, SW12 and SW13 to connect theselected battery unit and disconnect the discharged battery unit in thesame manner as described above.

Further, the discharge information is written into the memory of thebattery unit in use even when the request for operation of the electricdevice 1 by the driver 9 disappears at some midpoint of the discharge.

The action during operation of the electric device is explained inaccordance with flowcharts in FIG.9 and FIG. 10.

The controller 6 in FIG. 1 determines the existence or absence of therequest for operation of the electric device in the first step shown inFIG. 9, and if no operation request exists, it waits, and if exists, itimmediately proceeds to the next step to access the memory in the firstposition (the memory 11 of the battery unit 2 in the example of FIG. 1)to read its information. Then, the controller 6 determines whether theinformation is normal data (information) or not.

As a result, if the data is normal (Y), the controller 6 stores in apredetermined memory area the information in the first memory. Also inthis case, the controller 6 may set an installation flag in the samemanner as described above in the charge action, and access the memory ofthe battery unit every time the controller 6 needs the information inthe memory.

The controller 6 accesses, immediately when the result of the abovedetermination is abnormal (N) and after performing the above-describedprocessing when the result is normal (Y), the memory in the secondposition (the memory 12 of the battery unit 3 in the example in FIG. 1)to read its information. Then, the controller 6 determines whether theinformation is normal data (information) or not.

The controller 6 accesses, immediately when the result of the abovedetermination is abnormal (N) and after storing in a predeterminedmemory area the information in the second memory when the result isnormal (Y), the memory in the third position (the memory 13 of thebattery unit 4 in the example in FIG. 1) to read its information. Then,the controller 6 determines whether the information is normal data(information) or not.

When the result of the above determination is normal (Y), the controller6 stores in a predetermined memory area the information in the thirdmemory and then proceeds to operation processing shown in FIG. 10.

When the result of the above determination is abnormal (N), thecontroller 6 determines whether stored information exists in thepredetermined memory area or not, and when the information exits, thecontroller 6 proceeds to the operation processing shown in FIG. 10, andwhen no information exists, it determines that no battery units areinstalled in the first to third installation positions and ends thisprocessing here.

In the processing in the first step in FIG. 10, the controller 6compares the contents of the information stored in the predeterminedmemory areas, for example, selecting a battery unit having the leastremaining capacity, and controls the switches SW11, SW12 and SW13 by theSW1 n control signal to connect the selected battery unit to thecontroller 6 and the driver 9.

Then, the controller 6 allows the storage battery pack in the selectedbattery unit to discharge to thereby supply power to and drive the load10 in response to the operation request to operate the electric device1. While the remaining capacity of the storage battery pack of thebattery unit exists and the operation request is continued, the batteryunit keeps discharging. When the operation request disappears, thecontroller 6 writes the discharge information until then into the memoryof the selected battery unit and then ends the processing.

Once the controller 6 selects a battery unit to allow it to startdischarging, the controller 6 measures and calculates an integrateddischarge amount, temperature in discharging and the like which arepreviously decided as necessary in accordance with the batterycharacteristics and the electric device characteristics, during thedischarge, by the controlling function thereof by a predeterminedmethod, and holds them by the information storing function of thecontroller 6. Further, the controller 6 writes them into the memory ofthe selected battery unit as required.

On the other hand, when the selected battery unit comes into anend-of-discharge state at some midpoint while the operation request iscontinued, the controller 6 writes the discharge information until theninto the memory of the selected battery unit and other memories ifnecessary, for example, the memory for use in the information storingfunction included in the controller 6.

Subsequently, the controller 6 checks the information stored in theabove-described predetermined memory area to determine whether anotherdischargeable battery unit exists or not. In the case of “NO”, thecontroller 6 ends the processing, but in the case of “YES”, thecontroller 6 returns to the first step in FIG. 10 to repeat theabove-described processing, in which the controller 6 selects thebattery unit having the next less remaining capacity among the otherinstalled battery units to allow it to discharge to drive the loadduring the exist of the operation request.

FIG. 4 is a diagram showing a connecting state when the charger unit 8and the plurality of battery units 2, 3 and 4 are detached from theelectric device 1 shown in FIG. 1 to be charged, and the charge actionthereof is the same as the above-described charge action where they areinstalled in the electric device 1.

In this example, a state is shown in which the charger unit 8 and threesets of battery units 2, 3 and 4 are detached from the electric device 1at the same time to be charged, but it is not necessary to detach andcharge at the same time all of the plurality of battery units mounted onthe electric device 1.

For example, only the completely discharged battery unit or the batteryunit having a storage battery pack having a little remaining capacityamong the plurality of the battery units mounted on the electric device1 is detached together with the charger unit 8 and charged, which makesit possible to operate the load 10 in response to an operation requestby using the remaining battery units until the former battery unit ismounted again.

In the case where the charger unit 8 is fixedly provided in the electricdevice 1 or the battery units arc charged while mounted on the electricdevice, since the charger unit 8 needs to be connected to the commercialpower supply 100, the electric device 1 itself should be stopped at aplace where it can be connected to the commercial power supply 100, andthus the electric device 1 can not be used during the charge.Accordingly, the charge should be performed during hours when theelectric device is not in use such as during the night.

As in this embodiment, however, each of the charger unit 8 and thebattery units 2, 3 and 4 is detachably mounted on the main body of theelectric device 1, and only the charger unit 8 and a battery unitneeding to be charged are detached from the electric device 1 andcharged, which eliminates the need to connect the electric device 1 tothe commercial power supply, the load can be driven by using theremaining battery units also during the charge as described above forfree running.

It is preferable to prepare the charger unit 8, and a charging holderprovided with a charger unit installation section and battery unitinstallation sections in an integral manner, not shown, in which thecharger unit 8 and one or more battery units can be detachablyinstalled, and provided with a connecting cord to the commercial powersupply; and to provide, respectively in the charger unit installationsection and the battery unit installation sections, fixed terminals(connected to respective corresponding terminals of the charger unit 8and the battery unit 2 and the like), which form respective connectorsfor establishing electrical connection to the charger unit 8 and thebattery unit 2 and the like.

As a result, only by connecting the connecting cord of the chargingholder to the commercial power supply, installing the charger unit 8 inthe charger unit installation section, and installing battery unitsdesired to be charged in the battery unit installation sections, all theconnections between the connectors of the charger unit 8 and theinstalled battery units are completed, which allows charge to be startedimmediately.

The charger unit 8 and the charging holder can constitute the chargingapparatus according to the invention. In the case of the chargingapparatus which is not mounted on the electric device, the charger unit8 and the charging holder can be integrated to constitute the chargingapparatus.

Second Embodiment

FIG. 2 is a block circuit diagram of an electric device showing a secondembodiment of the invention on which battery units, are mounted, inwhich the same portions as those in FIG. 1 are assigned the samenumerals and the description thereof is omitted or simplified.

Battery units 22, 23 and 24 of the second embodiment include thereinrespectively, as in the battery units of the first embodiment, storagebattery packs 2B, 3B and 4B paired for integration with memories 11, 12and 13 for storing information about charge and discharge statesthereof, and chargers 25, 26 and 27 which are the same as the charger 5provided in the charger unit 8 in FIG. 1. Therefore, the battery units22, 23 and 24 can be referred to as power supply units.

Each of these battery units 22, 23 and 24 is detachably mounted on themain body of an electric device 1. The battery units 22, 23 and 24 andbattery unit installation sections (not shown) on the device main bodyare provided with connectors Ca1, Ca2 and Ca3, connectors Cb1, Cb2 andCb3, and connectors Cc1, Cc2 and Cc3, each of which is composed ofpaired terminals, as connecting means for performing electricalconnection and disconnection to/from the device main body respectivelyincident to attachment and detachment of the battery units 22, 23 and24.

On the electric device 1 of this embodiment, the charger unit 8 in FIG.1 is not mounted because the plurality of the battery units 22, 23 and24, which include therein chargers respectively are mounted. The otherconfiguration, that is, a controller 6, a controlling power supply 7, adriver 9 for driving a load 10 such as an electric motor or the like inresponse to a request from the controllers, and three switches SW11,SW12 and SW13 for switching the battery units for discharge (feed) by anSW1 n control signal from the controller 6 are provided, is the same asin the first embodiment.

The chargers 25, 26 and 27 of the battery units 22, 23 and 24 aredirectly connected to a commercial power supply 100 respectively, andconfigured to charge the respective storage battery packs 2B, 3B and 4Bin the same units referring to information stored in the respectivememories 11, 12 and 13 in the same units. While an example in whichthree sets of battery units are mounted is shown, two or more sets arepreferably mounted.

Next, charge action in the electric device of this embodiment isexplained.

When the chargers 25, 26 and 27 of the plurality of the battery units22, 23 and 24 are supplied with the commercial power supply 100 or analternative power supply, they go into the charge action.

Each of the battery units 22, 23 and 24 first accesses the memory 11, 12or 13 in the same unit, reads and obtains the information stored in thestorage battery pack 2B, 3B or 4B needing to be charged, and startscharging the storage battery pack when it determines that the storagebattery pack in the same unit needs to be charged. When the storagebattery pack is fully charged, the battery unit 22, 23 or 24 writes thecharge information into the memory in the same unit and ends the chargeaction.

When the charge action is stopped at some midpoint of the charge, thebattery unit 22, 23 or 24 writes the charge information until then intothe memory in the same unit in the same manner as in the case ofcompletion of the charge to utilize it for later charge and discharge.

The above-described charge action is one example in which the pluralityof the battery units 22, 23 and 24 separately perform charge action.However, when the plurality of the battery units perform charge actionsimultaneously, electric power is increasingly demanded of thecommercial power supply 100 or the alternative power supply, which mayproduce a disadvantage that a breaker stack trips in the case of, forexample, a household power supply.

As means for solving the above problem, as will be described below withreference to FIG. 12, control can be conducted such that the chargers25, 26 and 27 included in the respective battery units 22, 23 and 24 areconnected to each other by not shown connectors and signal lines, andthe chargers 25, 26 and 27 send/receive information each other throughan information exchange route by the signal lines to determine an orderof charging the storage battery packs 2B, 3B and 4B for sequentialcharge.

It is possible to cope with the above disadvantage, in accordance withthe contents of the information stored in the memories 11, 12 and 13, bypreparing a required commercial power supply or an alternative powersupply, by performing the sequential charge with the power demand beingmade appropriate to the power capacity of the commercial power supply orthe alternative power supply, or by controlling amounts of charge of theplurality of the storage battery packs 2B, 3B and 4B.

On the other hand, since the storage battery packs 2B, 3B and 4B areconnected to the chargers 25, 26 and 27 respectively all the time in thebattery units 22, 23 and 24 in this embodiment, it is necessary tointerpose, for example, diodes, reverse current preventing circuits, orthe like, not shown, between the storage battery packs and the chargersto prevent a current from reversely flowing from the storage batterypacks 2B, 3B and 4B to the charger units 25, 26 and 27.

Next, the above-described charge action in this electric device isexplained in more detail using flowcharts in FIG. 11 and FIG. 12.

The charge action in accordance with the flowchart in FIG. 11 is thecase in which the chargers 25, 26 and 27 in the respective battery units22, 23 and 24 shown in FIG. 2 separately perform charge action.

When the chargers 25, 26 and 27 of the battery units 22, 23 and 24 aresupplied with the commercial power supply 100 or the alternative powersupply, the respective chargers 25, 26 and 27 go into the charge actionshown in the flowchart in FIG. 11. While the same action is performed inany battery unit, the case of the battery unit 22 is explained below.

In the battery unit 22, the charger 25 first accesses the memory 11 anddetermines whether its data is normal or not. When the data is normal,the charger 25 determines the need to charge the storage battery pack 2Bbased on the information obtained from the memory 11. Then, when thecharger 25 determines that the charge is necessary, it starts chargingthe storage battery pack 2B. After the start of the charge, the charger25 continues the charge unless a command to stop the charge is given,and determines whether the charge has been completed or not, and when ithas been completed, the charger 25 writes the charge information at thattime into the memory 11 and ends the charge action.

After the start of the charge, the result of the access to the memory 11is not normal data, which is regarded as “error”, the charger 25 doesnot perform the charge action. In this case, the charger 25 goes intothe charge action again after taking measures, such as seeking a cause.When the result of the charger 25 determining the need to charge thestorage battery pack 2B based on the information obtained from thememory is that charge is unnecessary, the charger 25 ends the chargeaction there.

On the other hand, when a charge stop command is given after the startof the charge, the charger 25 writes the charge information until theninto the memory 11 even in charging and ends the charge action.

However, if the above-described charge action is performed in theplurality of the battery units simultaneously, demanded power isexcessively increased as has been explained, which may trip a breakerstack provided along the feed lines to the commercial power supply 100.

In order to prevent occurrence of the above disadvantage, it ispreferable to perform the sequential charge shown in the flowchart inFIG. 12.

In this case, a route through which information is sent/received isprovided among the chargers 25, 26 and 27 of the battery units 22, 23and 24 mounted on the electric device 1 shown in FIG. 2. This makes itpossible for the respective chargers 25, 26 and 27 to arbitrarily decidean order of charging the storage battery packs 2B, 3B and 4B byexchanging the information obtained from the memories 11, 12 and 13,respectively.

For example, there is a method of obtaining required amounts of chargefrom the remaining capacities of the storage battery packs based on theinformation obtained from the memories and converting them to time tocalculate required charging periods, and charging the storage batterypacks in order from the battery unit having the storage battery packrequiring a shorter charging period. There is also a method of chargingthe storage battery packs in order from the storage battery, pack havinga less capacity (most discharged), or a method of charging the storagebattery packs of the battery units in a predetermined order regardlessof the magnitude of the remaining capacities. Further, there is a methodof sequentially charging them from the storage battery pack having alarger charge capacity per unit time, and the like.

In the example shown in the flowchart in FIG. 12, in the first step, thecharger 25, 26 or 27 of the installed battery unit 22, 23 or 24sends/receives information to/from the chargers of other battery unitsto recognize the number of installed battery units individually and toobtain needs for charge and information of charging periods.

Then, the chargers 25, 26 and 27 determine the number of battery unitsneeding to be charged. As the result of the determination, when thenumber of battery units needing to be charged is three, the chargers 25,26 and 27 select two battery units from the battery unit requiring theshortest charging period and start charging their storage battery packs.When the number of battery units needing to be charged is not three, thecharger 25, 26 or 27 starts charging the battery unit needing to becharged.

The charger 25, 26 or 27 sends/receives information to/from otherbattery units to mutually obtain latest information about charge anddischarge states of the storage battery packs all the time during thecharge.

When a charge stop command is given during the charge, the charger 25,26 or 27 in charge action writes the charge information obtained untilthat time into the memory in the same unit and ends the charge action.

When a charge stop command is not given, the charger 25, 26 or 27continues the charge action and determines whether a battery unit forwhich the charge has been completed exits or not. As the result of thedetermination, when no charged battery unit exists, the charger 25, 26or 27 continues the charge action while sending/receiving informationamong the chargers.

When a battery unit for which charge has been completed exists, thecharger of the charged battery unit writes the charge information it hasat that time into the memory in the same unit.

Subsequently, the chargers 25, 26 and 27 further determine whether abattery unit needing to be charged exists or not based on thesent/received information among the chargers, and when a battery unitneeding to be charged exists, the chargers 25, 26 and 27 return to thedetermination whether the number of battery units needing to be chargedis three or not, repeat the above-described charge action to therebycharge the storage battery packs of the battery units needing to becharged.

Furthermore, after the completion of the charge, when the result ofdetermination whether a battery unit needing to be charged exists or notis “NO”, the chargers 25, 26 and 27 determine that charge for thestorage battery packs of all the battery units needing to be charged iscompleted and end the charge action.

Next, a process of limiting a charging electric power (an amount ofcharge) related to a charging electric power control in the secondembodiment is explained with flowcharts in FIG. 13 and FIG. 14.

It is difficult to suppress a charging current to decrease the chargingelectric power in a battery such as a Ni—Cd battery or a Ni-MH batteryin which a peak (with high accuracy) at −DV or DV is detected byconstant-current charging, but it is easy to suppress a charging currentto decrease the charging electric power in a battery such as a lithiumion battery or a lead battery by constant-voltage/constant-currentcharging.

Therefore, in the example described below, a function is provided whichcan control a charging current (electric power) regardless of the typeof the battery and further enables detection of a charging voltage and acharging current to calculate a charging electric power.

After the chargers 25, 26 and 27 of the plurality of the battery units22, 23 and 24 start the charging electric power controlling action shownin FIG. 13 using the commercial power supply 100, the charger of eachbattery unit installed in the electric device 1 first sends/receivesinformation to/from the chargers of other battery units to obtaininformation of the need to charge the installed battery units andcharging periods thereof.

Subsequently, the chargers determine whether a battery unit needing tobe charged exists or not, and when no battery unit needing to be chargedexists, the chargers end all the charge action there.

When battery units needing to be charged exist, charge is started in abattery unit requiring the shortest charging period below the electricpower from the commercial power supply and within the maximum capacityof the charger.

The electric power of the commercial power supply here can be obtained,for example, from the charging voltage, the charging current and theefficiency of the charger. Also after the start of the charge, each ofthe chargers of the plurality of the battery units sends/receives thecharge information including the electric power of the commercial powersupply by its charge controlling function. In the processing thereafteruntil the end shown in FIG. 14, the above-described processing isrepeated and the same processing as in the sequential charge which hasbeen explained with FIG. 12 are preformed, and thus the explanationthereof is omitted.

As described above, in this embodiment, the chargers 25, 26 and 27 graspthe charge information of all the mounted battery units bysending/receiving it among them all the time, and determine whether abattery unit needing to be charged next exists every time the charge hasbeen completed for any of the storage battery packs 2B, 3B and 4B of thebattery units 22, 23 and 24, or all the time at some midpoints duringthe charge.

When a battery unit needing to be charged exists, charge is started inthe battery unit requiring the next shorter charging period below theelectric power from the commercial power supply 100 and within themaximum capacity of the charger.

In other words, the charger of each battery unit grasps the chargeinformation of the chargers of all of the other battery units to therebygrasp the total electric power that each battery unit demands of thecommercial power supply 100.

By grasping the total electric power, each charger adjusts its owncharging electric power to enable parallel charge within the capacity ofthe commercial power supply 100 all the time.

For example, a battery such as a lithium ion battery, in which charge isperformed by a constant-current/constant-voltage method, hascharacteristics that the charge starts with a constant current, thecharging power is low when the voltage is low, it increases as thevoltage rises, it becomes maximum when the charge goes into a constantvoltage mode at a specified voltage, and thereafter the chargingelectric power decreases due to a decrease in charging current.

Each charger acts to a limit of allowable power of the commercial powersupply by utilizing the above-described characteristics that therequired charging electric power changes in accordance with the chargingstate, which enables an efficient charge. While this explanation isabout the battery which is charged by theconstant-current/constant-voltage method, the same effects can naturallybe obtained in a battery having other characteristics by grasping itscharacteristics and controlling charge.

In the example explained with FIG. 13 and FIG. 14, the charge is startedin order from the storage battery pack of the battery unit requiring theshortest charging period, which may be changed into a charge startingfrom the battery unit requiring the largest charging electric power, acharge starting from the battery unit requiring the smallest chargingelectric power, or the like. In any case, its purpose is achieved bydeciding the charge order suitable for the characteristics of thestorage battery pack and the characteristics of the electric device toperform charge.

The battery unit in which the storage battery pack has been chargedwaits until its charger writes the charge information into its memory atthat time by its charge controller and charge for all the battery unitsis completed, and all the charge is completed to thereby end the chargeaction. When the charge is stopped by shutdown of the commercial powersupply or charge stop operation, the chargers in the battery units forwhich charge action has been started write the charge information untilthen into the respective memories and end the charge action, in the samemanner as described above.

FIG. 5 is a diagram showing a charging method when a set of the batteryunit in FIG. 2 is detached from the electric device 1 to charge thestorage battery pack thereof, showing an example of the battery unit 22.The point differing from the above-described method of charging on theelectric device 1 is that the storage battery packs of the plurality ofthe battery units are not charged in sequence but the battery units 22,23 and 24 are separately detached from the electric device 1, thechargers 25, 26 and 27 are connected to the commercial power supply 100to charge the storage battery packs 2B, 3B and 4B in a single manner,and mounted on the electric device 1 again.

When the plurality of the battery units are detached, the battery unitsare connected such that the chargers thereof can send/receive the chargeinformation among them of the battery units in the same manner as whenthey are mounted on the electric device 1, which enables parallel chargeaction within the allowable power of the commercial power supply evenwhen the plurality of the battery units are connected to one outlet ofthe commercial power supply.

According to this embodiment, it is unnecessary to mount a charger uniton the electric device or to provide a separate charging apparatus, andthus the storage battery packs can be charged on an every-battery-unitbasis at any time and anywhere with only the commercial power supply.Further, when the storage battery packs of the plurality of the batteryunits are charged, the above-described sequential charge and chargingelectric power control can easily be conducted.

Third Embodiment

FIG. 3 is a block circuit diagram of an electric device showing a thirdembodiment of the invention on which battery units are mounted, in whichthe same portions as those in FIG. 1 are assigned the same numerals andthe description thereof is omitted.

Battery units 32, 33 and 34 of the third embodiment shown in FIG. 3include therein respectively, as in the battery units of the firstembodiment, storage battery packs 2B, 3B and 4B paired for integrationwith memories 11, 12 and 13 for storing information about charge anddischarge states thereof, and is provided with switches SWa, SWb and SWcin series with the storage battery packs 2B, 3B and 4B, respectively.

Each switch serves both as the switch SW21, SW22 or SW23 provided in thecharger unit 8 in FIG. 1 and the switch SW11, SW12 or SW13 controlled bythe controller 6 to reduce cost of products.

The battery units 32, 33 and 34 are detachably mounted on the main bodyof an electric device 1. The battery units 32, 33 and 34 arerespectively provided with series circuits composed of the storagebattery packs 2B, 3B and 4B and the switches SWa, SWb and SWc, controlterminals of the respective switches SWa, SWb and SWc, and terminals forconnecting the memories 11, 12 and 13 to the outside (terminals on therespective unit sides of connectors Ba1 to Ba6, connectors Bb1 to Bb6,and connectors Bc1 to Bc6).

Further, battery unit installation sections of the electric device 1 areprovided with fixed terminals of the connectors Ba1 to Ba6, theconnectors Bb1 to Bb6, and the connectors Bc1 to Bc6 for performingelectrical connection and disconnection to/from the aforementionedterminals incident to attachment and detachment of the battery units 32,33 and 34.

On the electric device 1 of the third embodiment, the above-describedplurality of the battery units 32, 33 and 34 are mounted, and a chargerunit 18 provided with a charger 5 is detachably mounted. This electricdevice 1 is the same as in the first embodiment shown in FIG. 1 in thatit further comprises a controller 6, a controlling power supply 7 and adriver 9 for driving a load 10 such as an electric motor or the like ata request from the controller 6, but it is not provided with theswitches SW11, SW12 and SW13 which are controlled by the controller 6.

The charger unit 18 is constituted such that the switches SW21, SW22 andSW23 in FIG. 1 are omitted from the charger unit 8 to separately outputan SW control signal to three connectors Cr1, Cr2 and Cr3, and threeearth-side connectors Cg1, Cg2 and Cg3 in FIG. 1 are integrated into oneearth-side connector Cg1.

In this embodiment, corresponding with the provision of the switchesSWa, SWb and SWc in the battery units 32, 33 and 34 respectively, thecharger 5 of the charger unit 18 separately opens/closes the switchesSWa, SWb and SWc in the battery units 32, 33 and 34 by the SW controlsignal based on the charge controlling function thereof.

The controller 6 can also separately open/close the switches SWa, SWband SWc in the battery units 32, 33 and 34 respectively by an SW controlsignal based on the charge controlling function thereof.

Here, priority is given to either the SW control signal from the charger5 or the SW control signal from the controller 6 and, for example, inthe case of giving priority to the charger 5, connection to thecommercial power supply 100 is detected and its information istransmitted to the controller 6 to inhibit the controller 6 fromoutputting the SW control signal, thereby securing normal actions of thethree switches SWa, SWb and SWc.

Further, connector circuits for supplying outputs of the non-switchedstorage battery packs 2B, 3B and 4B in the battery units 32, 33 and 34to the controlling power supply 7 are provided to perform supply ofrequired electric power to the controller 6 when any of the batteryunits is mounted, which is the function of the controlling power supply7.

Despite the difference that the switches SW21, SW22 and SW23 in thecharger unit 8 in the first embodiment shown in FIG. 1 are replaced withthe switches SWa, SWb and SWc respectively provided in the battery units32, 33 and 34, and that the SW2n control signal is replaced with the SWcontrol signal, the charge action in the electric device of the thirdembodiment is the same as the charge action in the first embodimentshown in FIG. 7 and FIG. 8 except for the above points, and thus theexplanation thereof is omitted here.

Despite the difference that the switches SW11, SW12 and SW13 shown inFIG. 1 are replaced with the switches SWa, SWb and SWc respectivelyprovided in the battery units 32, 33 and 34, and that the SW1 n controlsignal in the first embodiment (FIG. 1) is replaced with the SW controlsignal, the operating (load drive) action by the electric device 1 ofthe third embodiment is the same as the action by the electric device 1in the first embodiment shown in FIG. 9 and FIG. 10, except for theabove points, and thus the explanation thereof is omitted here.

FIG. 6 shows a state in which the charge is performed with the chargerunit 18 and the plurality of the battery units 32, 33 and 34 detachedfrom the electric device 1 shown in FIG. 3. The charge action thereof isthe same as the charge action in accordance with the first embodimentdescribed with FIG. 4, and thus the explanation is omitted.

It should be noted that the switches SW11, SW12 and SW13 in the batteryunits 22, 23 and 24 can also be omitted in the second embodiment shownin FIG. 2 by providing switches in series with the storage battery packs2B, 3B and 4B respectively in a manner to be on/off controllable fromthe outside.

Next, the most characteristic points of the invention, that is, effectsdue to the integration of the storage battery pack paired with thememory for storing information about the charge and discharge statesthereof to constitute the battery unit are explained.

The information to be stored in the memory of the battery unit accordingto the invention includes various kinds of information as follows,including at least the information about charge and discharge states ofthe battery (storage battery pack) in the same unit:

(1) Battery characteristics such as rated capacity of battery, chargecharacteristics, discharge load characteristics, cycle characteristics,preservation characteristics, temperature characteristics, and the like;

(2) History of charge and discharge such as voltage at the start ofcharge, integrated charge capacity, temperature in charging, integrateddischarge capacity, temperature in discharging, voltage at the end ofdischarge, remaining capacity, the number of discharge-cycles, chargeand discharge capacity results, temperature in use, and the like; and

(3) Correction data such as battery characteristics of capacity of thebattery, charge characteristics, and discharge load characteristics, andfundamental constant used for managing and controlling the battery, andthe like.

It is possible to store information of management in accordance with thebattery characteristics, information of environment and result of thebattery in use, correction information for each information based on useresult of the battery, information of characteristics of the electricdevice affecting the battery as required, and the like.

As described above, in this invention, it is possible to grasp all thetime the state of the battery characteristics such as the capacity ofthe battery (storage battery pack) in the battery unit, the chargecharacteristics, the discharge load characteristics, and the like byhandling the memory being integrated with the battery unit. As a result,the following many effects can be obtained:

(1) It becomes possible to use the battery under control of theremaining capacity by virtue of the memory of each battery unitregardless of the state of the battery, such as the battery beingcompletely (fully) charged, half charged, or during discharge, whichenables free exchange of the battery units.

(2) The determinations can be made to the charge order such thatcharging is performed starting from a battery unit having a smallerremaining capacity or from a battery unit having a larger remainingcapacity based on the information in the memory of the battery units; orcharging is performed starting from a battery unit having fewer chargeand discharge cycles based on the information of the number of thecorrection cycles to level the use rates of the battery units, or thelike, which makes it possible to perform charge starting from thebattery unit in accordance with user's will or suitable for thecharacteristics of the batteries and the electric device.

(3) The determinations can be made of the discharge order such thatdischarge is performed starting from a battery unit having a smallerremaining capacity based on the information of the memories of thebattery units, or starting from a battery unit susceptible to occurrenceof the memory effect based on the history information to increaseopportunities for the battery to discharge to a cutoff voltage so as toprevent the memory effect, when a battery in which a memory effectoccurs is in use, or discharge is performed starting from a battery unithaving fewer charge and discharge cycles to level the use rates of thebattery units, or the like.

(4) Charge after refresh can be automatically performed when there is apossibility of occurrence of the memory effect, or refresh can beautomatically performed only when the remaining capacity is below aspecified value, based on a capacity change rate of the charge anddischarge history information, information of repeating charge anddischarge, and the like, to shorten the refresh period.

(5) Based on the charge information and the discharge information in thecharge and discharge history information in the memories of the batteryunits, the charge and discharge orders are optimally decided to increasethe probability of complete charge or complete discharge, and correctionof the management of the remaining capacity of the battery is performedat a break of the charge and discharge action to improve the detectionaccuracy of the remaining capacity of the battery unit, which enables anappropriate operation of the electric device.

(6) It is possible to determine the battery life based on use historyinformation, such as the number of charge and discharge cycles, thecharge and discharge capacity results and the like, from the memories ofthe battery units to level the lives of the batteries by performingdischarge starting from, for example, a battery unit having fewercharges and discharges.

(7) Especially with a battery, such as a Ni—Cd battery, a Ni-MH batteryor the like, having characteristics that the memory effect occurs,discharge can be started from the a battery unit which is susceptible tooccurrence of the memory effect in the discharge order based on thecut-off voltage information of discharge in the charge and dischargehistory information to improve the rate of reaching the dischargecut-off voltage, which enables prevention of the memory effect.

(8) Batteries of the same type but having different capacities from eachother are managed based on battery characteristic information, such asthe rated capacity of the battery, the discharge load characteristicsand the like, the charge and discharge history information, and thecorrection data and the like from the memories of the battery units,which enables the use of the use batteries having different capacitiesin a mixed manner.

(9) Even when battery units provided with different types of batteriesexist in a mixed manner in a configuration composed of a plurality ofthe battery units, each battery is managed based on the batterycharacteristics information, the charge and discharge historyinformation, the correction data and the like in the memory of eachbattery unit, which enables the use of the different types of batteriesin a mixed manner.

(10) The batteries (storage battery packs) are paired for integrationwith the memories for storing the information such as the batterycharacteristics information, the charge and discharge historyinformation, the correction data and the like to constitute units whichare attachable/detachable to/from the electric device, which allows thebattery units to be shared in the electric device having a plurality ofbattery units, so that the charging of the batteries at a batterystation or the like can be facilitated.

(11) In the case of using an electric motor, the battery section isdivided into plural sections and the battery sections and the memoriesare integrated, which enables a larger regenerative electric power to berecovered by supplying its regenerative electric power to a battery ofthe mounted battery unit having a great depth of discharge to therebyimprove its recovery efficiency.

(12) By mounting a plurality of battery units having a requiredcapacity, only a single battery unit can operate the electric device,and other battery units can be charged even if the former battery unitis in operation.

(13) In the case in which the chargers are integrally provided in thebattery units respectively, the battery units can be simultaneouslycharged to shorten the charge periods.

INDUSTRIAL APPLICABILITY

As has been described, according to the invention, a battery sectionserving as a driving energy source of an electric device such as anelectric bicycle, an electric wheelchair or the like can be madeeasy-to-handle and efficiently used all the time.

In other words, detachment and carrying of the battery section by handis made easier, the electric device is not necessarily moved to a placewhere it can be connected to the commercial power supply for charging,and a special carrier device for transporting the battery section alsobecomes unnecessary.

Further, it also becomes possible to perform operation of the electricdevice provided with plural sets of battery sections and charge of thebattery sections concurrently, without requiring a special chargingapparatus. Furthermore, the battery characteristics of the batterysections can be managed, and thus charge and discharge of the pluralsets of battery sections can also be selected freely in accordance withrespective battery characteristics. Therefore, different types ofstorage battery packs become usable in combination.

It is also possible to prevent a so-called memory effect when asecondary battery (storage battery) such as a Ni—Cd battery in which thememory effect occurs is used as the battery section of the electricdevice, and further to eliminate the need for the refresh. This canprolong the battery life.

Further, a charging apparatus can be placed at a battery station tofacilitate charge, and the charge and discharge states can be recognizedwith a high accuracy even if the battery section is detached from theelectric device, which enables an optimal charge control all the time.

Moreover, it is also possible to recover the regenerative electric powerfrom the load side of an electric motor or the like to the batterysection efficiently and to use it effectively.

What is claimed is:
 1. An electric device, comprising: a plurality of battery units detachably mounted thereon, each battery unit constituted by pairing a storage battery pack with a memory for storing at least information about charge and discharge states of the storage battery pack; connectors provided on said each battery unit for performing electrical connection/disconnection to/from other elements of said electric device; a driver for driving a load and a controller for controlling supply of electric power from said each battery unit through said connectors to said driver by referring to the information stored in said memory of said each mounted battery unit; and a charger for charging said storage battery pack through said connectors by referring to the information stored in said memory of said each battery unit; wherein said charger includes means for reading at least information about charge and discharge states of the storage battery pack stored in said memory of said each battery unit, and means for writing into said memory at least the information about charge and discharge states of said storage battery pack in the same unit.
 2. An electric device according to claim 1, wherein said charger is provided in said each battery unit, and said charger has means for deciding a charge order by mutually referring to the information stored in said memory of said each mounted battery unit.
 3. An electric device according to claim 1, wherein a switch connected to said storage battery pack in series is provided in said each battery units, said charger is means for charging said each storage battery pack through said switch by referring to the information stored in said memory of said each battery unit, and said controller is means for controlling supply of electric power from said storage battery pack to said driver through said switch of said each battery unit by referring to the information stored in said memory of said each battery unit.
 4. An electric device according to claim 1, wherein said charger is constituted to be a unit attachable/detachable to/from said electric device main body.
 5. An electric device according to claim 3, wherein said charger is constituted to be a unit attachable/detachable to/from said electric device main body.
 6. An electric device according to claim 1, wherein said controller has means for reading the information stored in said memory of said each battery unit to control action of the whole device.
 7. An electric device according to claim 1, wherein said memory of said each battery unit also stores information about characteristics of said storage battery pack, and said charger has means for controlling charge of said storage battery pack, by referring to the information about the characteristics of said storage battery pack stored in said memory of said each battery unit, in accordance with the characteristics.
 8. An electric device according to claim 1, wherein said memory of said each battery unit also stores information about characteristics of said storage battery pack, and said controller has means for controlling discharge from said storage battery pack, by referring to the information about the characteristics of said storage battery pack stored in said memory of said each battery unit, in accordance with the characteristics.
 9. An electric device according to claim 1, wherein said controller has means for displaying a remaining capacity of said storage battery pack of said each battery unit based on the information stored in said each battery unit, and displaying a charge request, giving an alarm, or both when a storage battery pack needing to be charged exists.
 10. A method for charging and discharging a battery unit in an electric device comprising: a plurality of battery units detachably mounted thereon, each battery unit constituted by pairing a storage battery pack with a memory for storing at least information about charge and discharge states of the storage battery pack; a driver for driving a load; a controller for controlling supply of electric power from said each battery unit to said driver; and a charger for charging said storage battery pack of said each battery unit, comprising the steps of: discharging at different times the storage battery packs of said respective mounted battery units, and then charging them by said charger under the control of said controller, by referring to the information stored in said memories; and writing into said memory at least the information about charge and discharge states of said storage battery pack in the same battery unit.
 11. A method for charging and discharging the battery unit in the electric device according to claim 10, wherein the step of discharging and charging is a step of discharging the storage battery packs of said respective mounted battery units in decreasing order of remaining capacity, and charging them in increasing order of remaining capacity, by said controller and said charger, by referring to the information about charge and discharge states stored in said memories.
 12. A method for charging and discharging the battery unit in the electric device according to claim 10, wherein the step of discharging and charging is a step of discharging the storage battery packs of said mounted battery units in increasing order of remaining capacity, and charging them when the remaining capacities become a predetermined value or less, by said controller and said charger, by referring to the information about charge and discharge states stored in said memories.
 13. A method for charging and discharging the battery unit in the electric device according to claim 10, further comprising the steps of: selecting one or more of said battery units by said controller and said charger by referring to the information about charge and discharge states stored in said memories; and selecting remaining one or more of said battery units by said controller and said charger by referring to the information about charge and discharge states stored in said memories, and wherein the step of discharging and charging is a step of discharging each of storage battery packs of former selected battery units, and charging each of storage battery packs of latter selected battery units, by said controller and said charger, by referring to the information about charge and discharge states stored in said memories of said mounted battery units.
 14. A method for charging and discharging the battery unit in the electric device according to claim 10, wherein the step of discharging and charging is a step of discharging in order the storage battery packs of said respective mounted battery units to a predetermined remaining capacity, and then charging them, by said controller and said charger, by referring to the information about charge and discharge states stored in said memories. 